I don't understand this notion.
If you buy a Nintendo system, you get access to the best 1st party library every gen.
If you're eager to play some 3rd party games in addition, I recommend to play them on PC. Steam makes PC gaming feel more and more like a PC/console hybrid anyway, with more and more Japanese games coming (e.g. Tales of Zestiria) and with the by far best library of western games on any system. I play all my multiplats on TV hooked to my PC with an X360 controller.
So no, it has never been a bad time to own a Nintendo system.
It's not only the system with the best exclusives every gen, it's also the only system which never (or only very rarely) loses the "true exclusive" status of their titles.